so i went from a sp2 back to stock and i guess i stripped the bolt because when i put in the last section (mid pipe=> muffler) one bolt doesn't thread...and i used a impact gun with a new bolt and it still doesn't thread? im guessing that the threading is fucked up.. any help?

 

You may have to re-tap the threads.

 

how do you do that?

 

You use a metric tap and die set.

 

are those inexpensive and easy to use?

 

The prices vary depending upon the set (you can find a decent one for less than $100) and they're pretty simple to use.